Safety switch



July 16, 1940. COLBY 2,298,179

SAFETY SWITCH Filed March 1, 1938 3 Sheets-Sheet l T0 LINE July 16, 1940. F. COLBY 2,203,179

I SAFETY SWITCH Filed March 1, 1958 s Shets-Sheet z HHH WUUIM.

fled 60,163,

July 16, 1940. COLBY SAFETY SWITCH Filed March 1, 1938 3 Sheets-Sheet 3 M," n00 UM Patented July 16,1940

UNITED STATES PATENT OFFICE 10 Claims.

My invention relates to means for making and breaking electrical circuits such as are employed in lighting, household appliances, electrically operated signs, gasoline stations, automobiles. motor boats and related arts.

My invention further relates to circuit interrupters and particularly to fluid circuit interrupters, and has for one of its objects to provide a relatively simple, compact and rugged construction of fiuid circuit interrupter that shall be effective to interrupt an electrical circuit by either manual or automatic operation.

It is a further object of my invention to provide a circuit maker and breaker of the fluid type which is simple in operation and capable of installation in any conventional circuit, the main function of said circuit maker and breaker being to eliminate the fire hazards resulting from short circuits.

A still further object of my invention is to provide a novel switch for use particularly on automobiles, adapted to automatically break the connection between the battery and the circuits of the electrical system when the automobile overturns, to prevent short circuits and thereby prevent explosion of spilled gasoline, and to eliminate fire hazards in general. After an automobile has overturned, and the circuit automatical-- ly broken, it is often desirable to again close the circuit in order to sound the horn or turn on the lights of the automobile, and a specific object of this invention contemplates the provision of manual means associated with the automatic means whereby the automatically broken circuit can be closed.

A further object of my invention relates to a novel form of switch having a plurality of leads therein and means within the switch to connect the various leads in such manner as to control the fiow of electricity through the switch.

Still another object of my invention contemplates the use of my switch in a battery structure or in series with batteries whereby to enable manual control of said battery or batteries.

Other objects and advantages of the invention will appear as the description of the drawings proceeds. I desire to have it understood, however, that I do not intend to limit myself to the particular details shown or described, but that I intend to include as part of my invention, all such obvious changes and modifications as would occur to persons skilled in this art.

For accomplishing the above objects of the invention, a switch has been constructed as hereing omitted.

in shown and described, and for a complete understanding of the invention, reference is to be had to the following description considered with reference to the accompanying drawings.

In the drawings:

Fig. 1 is a vertical sectional view through the switch showing the same in use in a light circuit.

Fig. 2 is a transverse sectional view of the switch and taken substantially on line 2-2 of 10 Fig. 1.

Fig. 3 is a vertical sectional view of a modified form of switch.

Fig. 4 is a partial sectional view of a motor vehicle with my invention built into the same. 15

Fig. 4a is a plan view of my invention as applied to a motor vehicle.

Fig. 5 is a vertical sectional view of a modified form of switch, the upper wall of the switch be- Fig. 6 is a transverse sectional view taken on line 6-6 of Fig. 5.

Fig. 7 is a vertical sectional view of a further modified form of switch, the upper wall of the switch being omitted.

Fig. 8 is a transverse sectional view taken on line 8-8 of Fig. 7.

Fig. 9 is a vertical sectional view of a still further modified form of switch, the upper wall of the switch being omitted. 30

Fig. 10 is a plan view of the switch as employed between two battery cells, the major portions of the battery being omitted.

Fig. 11 is a vertical sectional view of the arrangement disclosed in Fig. 10 and taken on the 35 line HIl of Fig. 10.

Fig. 12 is a view similar to Fig. 11 and showing a modified form of the switch.

Fig. 13 is a top plan view of a switch shown built into a side wall of the battery.

Referring to the drawings in detail, and more particularly to Fig. 1, the reference numeral l indicates the casing which is preferably cylindrical and is formed of insulating material, and 2 and 3 indicate two electrodes which are of arcuate form and embedded in the casing. The electrodes 2 and 3 have terminals 4 and 5 respectiveare of such size as to terminate a predetermined listance from each other at each of their ends. Between the ends of each pair of electrodes is provided a channel la which extends substantially t ough the length of the upper and lower chamb s formed in the casing I. These electrodes extend circumferentially of the casing and ly which may be connected to a lighting system.

designated generally at 6. The numeral 1 designates a piston means shown in operative position immersed in a current conducting fluid la. The piston is preferably formed with rounded ends, top and bottom, as shown at lb. Through this formation of piston a retentive reservoir for a portion of the conducting fluid is always provided below the piston, irrespective of how the switch is turned in operating position. This reservoir indicated at 1c cooperates with the channels la in the casing wall to maintain a supply of conducting fluid between the ends of the electrodes 2 and 3 under such operating conditions as described later in connection with Fig. 9. Ordinarily, mercury will be used as the fluid in the chamber, but other conductive fluids may be employed without detriment to the parts in contact with the fluid, all the parts being preferably made of non-corrosive materials.

As shown in Fig. 1, when the piston is in the operative position, the fluid Ia fills the space immediately above the piston and between the opposed faces as well as bridging the spaces between the ends of the electrodes 2 and 3 and thereby completes the circuit through the terminals d and 5. Normally, when the piston is in raised position to occupy the upper end of the casing, the fluid in the casing will assume a level a slight distance below the electrodes. In this position of the fluid level, the circuit will be broken. In order to maintain contact between the ends of the electrodes, the casing may be provided with the vertically extending channels la formed in the casing wall between the ends of the electrodes, as above described, said channels bridging the gap between the respective ends of the electrodes. This feature will be further discussed in the description of Fig. 9.

For the purpose of operating piston 1, said piston is provided with a rod member 8 having a cross member 8a. The piston, rod member and cross member may be of insulating material and is formed in two parts having a threaded connection as seen at 9 for the purpose of permitting assembly of the same.

A closure assembly is provided for sealing the casing and comprises an inner plate l0 having a central opening H for frictionally receiving the piston rod 8. An enlarged opening l2 in the plate l0 contains a suitablej packing material l2a, and closing this opening an outer plate l3 including an opening l4 corresponding to opening H for receiving rod 8. Plate l3 further includes an overlying shoulder l3a for retaining and compressing the packing material. Threaded bolts l5 are employed to secure the closure plates in position and in order to obtain a more positive retention of said bolts, I employ metal anchoring members I6 embedded in the material of the casing body.

For the purpose of retaining the piston at various elevations, I have provided a spring steel strip I! which is corrugated as shown at I la. Although spring steel is employed a non-corrosive metal or a strip of molded material could be used in place of said spring steel. The spring strip I! is locked to the casing by the bolts l5 and may be split at its upper end to obtain increased resiliency. At the upper end of rod 8, I provide an enlarged portion l8, said portion cooperating with the corrugated portions to hold the piston at various elevations as will be readily understood.

In the normal use of the present switch member, the piston is raised and lowered a great many times, and due to the frictional fit between the piston and the casing, and due to the frictional resistance ofiered by the conducting fluid, there is a possibility that a thin film of oxide or other conducting material may adhere to the casing wall between the reservoir and electrodes 2 and 3 so as to maintain the circuit when the piston is raised. To insure against this possibility, I provide grooves or notches l9 and 20 which form a break in the casing and the grooves thus prevent the current from creeping down the side of casing to mercury in reservoir and creating a false circuit when piston is at top. The same is true in the reverse position of the piston.

In the modified form shown in Fig. 3, the casing 2| includes an inner chamber having a tapered cylindrical wall 22. The electrodes 23 and 24 of this form have complementary tapered portions as seen at 25 and 26, portion 26 being contiguous with wall surface 22. The upper wall portion of this casing has a cylindrical restricted portion 21 adapted to receive elongated cylindrical portion 28 of the closure member 29. The inner surface of said portion 28 is inwardly tapered as seen at 30 and is contiguous with the tapered portions 25 of the terminals 23 and 24.

As described in connection with Fig. 3, closure member 29 has a central opening 3| through which an operating rod member 32 passes, said rod member carrying piston 33. Above opening 3| in the closure member, there is provided a packing gland 34 receiving packing 35. Formed integrally with the closure member, there is an extension 36, said extension being internally threaded to receive a threaded closure plug 38. The closure plug is centrally bored as at 37 to receive the upper portion of the operating rod 32, said closure plug being further provided with an enlarged bored portion 38a to receive casing 39 which is held in place by a horizontally disposed screw 40. The casing 39 receives the upper part of the operating rod and the same is held in tight frictional engagement. The conventional Bowden wire mechanism may be employed if so desired.

The piston 33 has upper and lower tapered portions ll and 42 corresponding to the upper and lower tapered walls 22 and of the chamber within the casing. Through the use of the tapered portion of the piston and casing, substantially all frictional contact is eliminated during the raising and lowering of the piston. It is also to be noted that the particular arrangement of the closure plug and the packing produces an entirely leakproof casing, preventing the escape of any fluid from the casing, and also preventing the entrance of explosive fumes or liquids to casing of switch. The construction is also of such nature as to permit ease of assembly and the ready replacement of any worn out parts.

In Fig. 4 of the drawings, I have shown my invention as applied to a motor vehicle, showing a transverse section of the same, disclosing only those parts of the vehicle necessary to illustrate the invention. The conventional parts of the vehicle shown are floor board 43, seat 44, battery 45 having one terminal connected to the line circuit designated generally by the numeral 46, and the other terminal grounded on the automobile chassis frame 21. Mounted between the battery spoon-re stood, however, that the entire switch as shown in Fig. 3 may be used if so desired.

As shown in Fig. 4 the door board 43 of the vehicle is provided with an opening 49 for receiving tubing 39, the tubing being secured in any .conventional manner to the floor board. The

upper end of the rod 32 is formed into a handle portion 50 for operating the piston member. The switch is connected to chassis frame 41 by means of a metal bracket 48, said bracket also receiving terminal 5 of the switch and serves to ground same to the chassis frame. Terminal 4 of the switch is connected to the battery terminal as shown at 4811.

The operation of the switch in an automobile is as follows:

As seen in Fig. 4, when the car is upright, the piston is in its lowered position, causing the fluid in the casing to contact the electrodes of the casing, thus completing the electrical circuit of the vehicle and enabling the same to operate. If the vehicle should completely overturn, the fluid in the casing will flow to that part of the casing opposite to the parts containing the piston and will break contact between the electrodes thus breaking the electrical circuit of the vehicle.

If the vehicle overturns on its side, whether it be on the right or left side, the fluid will seek the lowest part of the casing, which casing in either of these positions will be horizontally disposed. In this position of the casing, the fluid will no longer contact the ends of the electrodes and the circuit will be broken as will be clearly apparent.

'Thus, it will be seen that there can be no short circuiting of the electrical system of the vehicle, thereby eliminating the presence of any sparks which might tend to set flre to the vehicle. However, after overturning of the vehicle, it may be very desirable to again complete the circuit so as to provide lighting facilities, or to permit sounding of the vehicle horn. In order to obtain this result, it is only necessary to grasp the handle 58 and by pulling the same, the piston will be moved to the opposite end of the casing forcing the fluid into contact with the electrodes and thus completing the circuit.

In Fig. 5, I have disclosed a modified form of the casing shown in Fig. l.- The modification relates to the specific construction of the electrode connected to the source of power. Referring to said Fig. 5, the parts corresponding to similar parts in Fig. 1, are casing l, electrode 2 and notches l9 and 2B. The piston and fluid, not shown, operate in the same general manner as in Fig. 1. As seen at the right of the figure, I have provided a multiple contact terminal, herein shown as three although any number of terminals may be used. The multiple contact terminal comprises three electrodes 5!, 52 and 53, each of which is embedded in the casing and is separated by the insulating material of the casing. The upper edge of electrodes 53 issubstantially in the same plane as the upper edge of the common electrode 2, whereas the lower edge of electrode 5i is substantially in the same plane as the lower edge of electrode 2. Each of the electrodes iii, 52 and 53 is connected up to different sources of power. Also shown in this figure are mounting members 54 and 55. These mounting members are embedded in the material of the casing and may be used in any of the modified casings.

The operation of this form of the invention is as follows: When a small current is desired, the piston is only partially immersed in the fluid of the casing, forcing the level ofthe fluid to rise and thus contact the electrodes 2 and II thereby bringing in the first source of power. To increas the current, the piston is lowered until the level of the fluid'reaches the level of electrode 82, thereby bringing in the second source of power. To further increase the current flowing through the circuit, the piston-ls again lowered until the level of fluid reaches electrode 53, thereby bringing in the third source of power. The advantages of such a construction is readily apparent.

In Fig. 7, I have disclosed another modification, corresponding to Fig. 5 with the exception that the electrode on the left of the figure also comprises a multiple contact terminal and includes three electrodes corresponding to the electrodes on the right of the figure. These electrodes are shown at 56, 51 and 58 and with their corresponding electrodes SI, 52 and 53, form three separate complete the secondcircuitfand still further movement of the piston will complete the third circuit. This form of the switch may be employed in lighting signs, by connecting the terminals on the left of the figure to different letters of sign and attaching the piston of the casing to a reciprocating motor whereby the letters of the sign may be alternately turned on and oil.

In the modified form shown in Fig. 9, the casing is provided with a spiral groove or channel 59 which is formed in the casing and bridges the gap between the ends of the electrodes. This form of the invention is particularly adaptable for use in motor boats. Due to the presence of the spiral grooves there is always contact between the electrodes regardless of the position of the boat while in motion. When the boat overturns, the circuit is automatically broken in the same manner as explained in connection with the switch shown in Fig. 4. Although spiral grooves or channels are employed in Fig. 9, straight vertical channels may be substituted for said spiral grooves as stated in connection with thedescription of Fig. 1.

In Figs. 10-13 inclusive, I have shown my switch as applied to a series of battery cells, wherein it is desirable to manually control battery circuits. Referring to Figs. 10 and 11, the battery cells are designated at Bil and Si, the major portions of said cells being broken away, and battery posts 62 and 63, forming connections for electrodes 86 and 61 which are built into switch casing 54. Numeral 65 denotes the fluid chamber of the casing. The piston member, not shown, corresponds in shape to the shape of the casing.

In Fig. 12, the casing is slightly modified to permit the cells to be more closely spaced. The various parts of this form are similar to parts shown in Fig. 11 with the exception of the electrodes 68 and 69 which are straight instead of angular.

In Fig. 13, I have shown my switch built directly into one of the walls of the battery. In this figure, numeral 10 denotes the battery, 1! the switch and i2 and 13 the electrodes. The ends of the electrodes are bridged by the insulating material of the battery. The numerals i i and i6 designate the switch terminal hookups and 15 denotes the battery terminal. The strap ll bridges the terminals 15 and 16. The usual battery cables, not shown, are hooked up with 75 terminals 14 and 1s. 1: any trouble should develop in the switch H, the battery cable may be transferred from switch terminal 14 to terminal 16. Thus it will be seen that the construction herein shown and described are well adapted to accomplish the objects of the present invention. It will be understood, however, that the invention may be embodied otherwise than here shown and that in the embodiments illustrated, certain changes in the construction and arrangements may be made. Therefore, I do not wish to be limited precisely. to the construction herein shown except as may' be required by the appended claims considered with reference to the prior art.

Having thusdescribed the invention, what is claimed is:

1. In a switch device, a sealed casing of insulated material, electrodes on the wall of said casing substantially midway between the bottom and top walls of said casing, said walls tapering inwardly from said electrodes to the top and bottom walls of the casing, a current conducting fluid in the lower part of the casing terminating below the electrodes and a piston in said casing, said piston corresponding in taper to the taper of the casing walls and being movable into the fluid to cause said fluid to rise and contact the electrodes to complete the circuit between the electrodes.

2. A device in accordance with claim 1, and means connected to said piston and passing through the casing and adapted to be manually manipulated to provide reciprocal movement for said piston.

3. In a switch device, a casing of insulated material provided with electrodes having their ends spaced apart, said electrodes being spaced from the bottom of the casing and embedded in the wall of the casing coincident with the inner surface of the casing and channels in the form of spirals formed in the wall of the casing and bridging the gaps between the ends of the electrodes.

4. In a switch device, a sealed casing of insulating material provided with electrodes on the wall of said casing midway between the upper and lower wall portions and defining upper and lower chambers which are substantially similar to each other, said electrodes being of arcuate form and extending circumferentially of the cas-' ing wall, the ends of the electrodes being spaced apart, said electrodes being embedded in the wall of the casing and coincident with the inner surface of the case, a current conducting fluid in the casing and terminating below the electrodes, means operable-on said fluid to cause said fluid to rise and thereby contact the electrodes and thus complete the circuit between the electrodes, and circumferential notches in the wall of the casing immediately above and below the electrodes.

5. In a switch, a sealed casing of insulating material provided with electrodes mounted on the wall of said casing substantially midway be tween the upper and lower wall portions and defining upper and lower chambers substantially identical to each other, said electrodes being spaced apart, a current conducting fluid in the casing normally terminating below the electrodes,

' a piston within the casing, said piston being movable intoa fluid chamber to cause the fluid to riseand bridge the gap between the electrodes thereby completing the circuit, and when the casing is in inverted position, movable into the other of said chambers to cause the fluid to contact the electrodes.

6. A device'inaccordance with claim 5, and circumferential notches in the wall of the casing immediately above and below the electrodes.

7. A device in accordance with claim 5, means connected to said piston'and passing through the casing and adapted to be manually manipulated toprovide reciprocal movementior the piston, and means associated with said first mentioned means to lock said piston in various selected positions.

8. In a switch, it sealed casing of insulating material provided with electrodes mounted on the wall of said casing substantially midway between the upper and lower wall portions and defining upper and lower chambers substantially identical to each other, said electrodes embedded in the wall of the casing with their ends spaced apart, a current conducting fluid in the casing terminating below the electrodes, a piston closely fitting within the casing, said piston being movable into the fiuid chamber to cause the fluid to rise and bridge the gap between the electrodes thereby completing the circuit, and when the casing is in inverted position, movable into the other of said chambers to cause the fluid to contact the electrodes.

9. In a switch, a sealed casing of insulating material, electrodes mounted on the wall of said casing substantially midway between the upper and lower wall portions and defining upper and lower piston receiving chambers, said electrodes having their ends spaced apart, a current conducting fluid in the casing terminating below the electrodes when the casing is in upright or inverted positions, a piston within the casing, said piston being movable into the lower fiuid chamber to cause the fluid to rise and bridge the gap between the electrodes thereby completing the circuit, and when the casing is in inverted position, movable into the other of said chambers to cause the fluid to contact the electrodes.

10. In a switch of the class described, a sealed casing of insulating material provided with electrodes mounted on the wall of said casing substantially midway between the upper and lower end portions thereof and defining upper and lower chambers substantially identical to each other, 'the ends of said electrodes being spaced apart by a channel in the casing wall extending between the remote ends of said chambers, a current conducting fluid in said casing normally terminating below said electrodes, a piston within said casing, said piston having its ends formed for selective cooperation with the remote ends of said upper and lower chambers to provide therewith retentive reservoirs for a portion of the conducting fluid, means extending into said casing and connecting said piston to move the same into the chamber containing said fluid and adjacent the lower end of the casing, whereby to cause the fluid to rise through said channel between the ends of said electrodes and also bridge said electrodes across the top of said piston.

FRED COLBY. 

